Electronic Pen and Electronic Pen Main Body Unit

1. An electronic pen comprising: a first casing; a second casing disposed within the first casing; and an electronic pen main body unit incorporating an electronic pen function disposed within the second casing, wherein the electronic pen main body unit includes a side switch unit having a side switch knob exposed on a side surface of the second casing, wherein: an operating opening portion is disposed in a side surface of the first casing, and the operating opening portion exposes to an outside of the electronic pen the side switch knob of the side switch unit of the electronic pen main body unit exposed on the side surface of the second casing, a length of the operating opening portion in a longitudinal direction of the first casing is greater than a length of the side switch knob of the side switch unit of the electronic pen main body unit in the longitudinal direction of the first casing, the side switch knob of the side switch unit of the electronic pen main body unit is slidingly movable in the longitudinal direction of the first casing between a first position and a second position within the operating opening portion, when the side switch knob of the electronic pen main body unit is at the first position in the longitudinal direction of the first casing, a pen tip of the electronic pen main body unit protrudes from a front end of the first casing, when the side switch knob of the electronic pen main body unit is at the second position in the longitudinal direction of the first casing, the pen tip of the electronic pen main body unit does not protrude from the front end of the first casing, and the side switch knob of the electronic pen main body unit is exposed through the operating opening portion to the outside of the electronic pen when the side switch knob of the electronic pen main body unit is at both the first position and the second position.

2. The electronic pen according to claim 1 , wherein: the pen tip of the electronic pen main body unit protrudes from the front end of the first casing when the side switch knob of electronic pen main body unit is slidingly moved towards the front end of the first casing to the first position in the longitudinal direction of the first casing, and the pen tip of the electronic pen main body unit does not protrude from the front end of the first casing when the side switch knob of electronic pen main body unit is slidingly moved away from the front end of the first casing to the second position in the longitudinal direction of the first casing.

3. The electronic pen according to claim 2 , further comprising: a state retaining mechanism that retains a state in which the pen tip of the electronic pen main body unit protrudes from the front end of the first casing, wherein the state retaining mechanism slidingly moves the electronic pen main body unit in a direction of a rear end of the first casing that is opposite a pen tip side of the first casing to house the pen tip within the first casing when a cancelling operation that cancels the state in which the pen tip protrudes from the front end of the first casing is performed.

4. The electronic pen according to claim 3 , wherein: the state retaining mechanism includes: an elastic member that biases the electronic pen main body unit in the direction of the rear end of the electronic pen main body unit when the pen tip protrudes from the front end of the first casing, and a locking protruding portion disposed on the second casing and acting to maintain a biased state of the elastic member by engagement with a locking opening portion disposed in the first casing, and the cancelling operation is an operation of cancelling the engagement of the locking protruding portion with the locking opening portion.

5. The electronic pen according to claim 2 , wherein: a core body including the pen tip is disposed on a pen tip side of the electronic pen main body unit, and a ferrite core is disposed on a periphery of a side surface of the core body.

6. The electronic pen according to claim 1 , wherein: the side switch knob is configured to protrude from the side surface of the second casing.

7. The electronic pen according to claim 1 , further comprising: a knock mechanism that enables a transition to a state in which all of the electronic pen main body unit is housed within the first casing and a state in which a pen tip of the electronic pen main body unit protrudes outside of the first casing, wherein the side switch knob becomes operable through the operating opening portion of the first casing when the pen tip of the electronic pen main body unit protrudes outside of the first casing.

8. The electronic pen according to claim 1 , wherein: the electronic pen main body unit includes a resonance circuit including an inductor and a capacitor in the second casing.

9. The electronic pen according to claim 8 , wherein: the electronic pen main body unit includes a capacitor that changes a frequency of an oscillated signal and that is disposed so as to be connectable to the resonance circuit, and the capacitor is selectively connected to the resonance circuit according to an operation of the side switch knob.

10. The electronic pen according to claim 1 , wherein: the electronic pen main body unit includes a transmitting circuit.

11. The electronic pen according to claim 10 , wherein: the electronic pen main body unit includes a capacitor that changes a frequency of an output signal and that is disposed so as to be connectable to the transmitting circuit, and the capacitor is selectively connected to the transmitting circuit according to an operation of the side switch knob.

12. The electronic pen according to claim 1 , wherein: the electronic pen main body unit includes a signal transmitting circuit which, in operation, generates a signal based on a pressure applied to the pen tip of the electronic pen main body unit, wherein, when the side switch knob of the electronic pen main body unit is at the first position in the longitudinal direction of the first casing, the side switch knob of the electronic pen main body unit is electrically coupled to signal transmitting circuit, and wherein, when the side switch knob of the electronic pen main body unit at the second position in the longitudinal direction of the first casing, the side switch knob of the electronic pen main body unit is not electrically coupled to signal transmitting circuit.

13. The electronic pen according to claim 1 , wherein: the electronic pen main body unit includes: a coil; and a pen pressure detector having an electrical characteristic which, in operation, varies based a pressure applied to the pen tip of the electronic pen main body unit, when the side switch knob of the electronic pen main body unit is at the first position in the longitudinal direction of the first casing, the pen pressure detector is electrically coupled to the coil, and when the side switch knob of the electronic pen main body unit is at the second position in the longitudinal direction of the first casing, the pen pressure detector is not electrically coupled to the coil.

14. The electronic pen according to claim 1 , wherein: the electronic pen main body unit includes a coil, when the side switch knob of the electronic pen main body unit is at the first position in the longitudinal direction of the first casing, the side switch knob is electrically coupled to the coil, and when the side switch knob of the electronic pen main body unit is at the second position in the longitudinal direction of the first casing, the side switch knob is not electrically coupled to the coil.

15. An electronic pen main body unit that performs an electronic pen function of an electronic pen that includes a first casing, the electronic pen main body unit comprising: a second casing configured to be disposed within the first casing; and a side switch unit having a side switch knob exposed on a side surface of the second casing and operable from an operating opening portion disposed in a side surface of the first casing, wherein: the side switch knob of the side switch unit exposed on the side surface of the second casing is configured to be exposed to an outside of the electronic pen by the operating opening portion of the first casing, a length of the operating opening portion in a longitudinal direction of the first casing is greater than a length of the side switch knob of the side switch unit of the electronic pen main body unit in the longitudinal direction of the first casing, the side switch knob of the side switch unit of the electronic pen main body unit is slidingly movable in the longitudinal direction of the first casing between a first position and a second position within the operating opening portion, when the side switch knob of the electronic pen main body unit is at the first position in the longitudinal direction of the first casing, a pen tip of the electronic pen main body unit protrudes from a front end of the first casing, when the side switch knob of the electronic pen main body unit is at the second position in the longitudinal direction of the first casing, the pen tip of the electronic pen main body unit does not protrude from the front end of the first casing, and the side switch knob of the electronic pen main body unit is exposed through the operating opening portion to the outside of the electronic pen when the side switch knob of the electronic pen main body unit is at both the first position and the second position.

16. The electronic pen main body unit claim 15 , further comprising: a signal transmitting circuit which, in operation, generates a signal based on a pressure applied to the pen tip of the electronic pen main body unit, wherein, when the side switch knob of the electronic pen main body unit is at the first position in the longitudinal direction of the first casing, the side switch knob of the electronic pen main body unit is electrically coupled to signal transmitting circuit, and wherein, when the side switch knob of the electronic pen main body unit at the second position in the longitudinal direction of the first casing, the side switch knob of the electronic pen main body unit is not electrically coupled to signal transmitting circuit.

17. The electronic pen main body unit claim 15 , further comprising: a coil; and a pen pressure detector having an electrical characteristic which, in operation, varies based a pressure applied to the pen tip of the electronic pen main body unit, wherein: when the side switch knob is at the first position in the longitudinal direction of the first casing, the pen pressure detector is electrically coupled to the coil, and when the side switch knob is at the second position in the longitudinal direction of the first casing, the pen pressure detector is not electrically coupled to the coil.

18. The electronic pen main body unit claim 15 , further comprising: a coil, wherein: when the side switch knob is at the first position in the longitudinal direction of the first casing, the side switch knob is electrically coupled to the coil, and when the side switch knob is at the second position in the longitudinal direction of the first casing, the side switch knob is not electrically coupled to the coil.